The 1961 Conservation Treatment of The Gross Clinic

In 1961, a Thomas Eakins retrospective exhibition appeared in Washington, D.C., Chicago, and then finally in Eakins’s native city, Philadelphia. It was considered essential that the exhibition include his celebrated masterpiece, The Gross Clinic, but when the Philadelphia Museum of Art’s conservator, Theodor Siegl, examined the painting, he recognized that it was far too fragile to travel. Because the lightweight linen canvas on which it was painted became brittle and weak as it aged, in 1915 a restorer, T. H. Stevenson, “lined” the painting, reinforcing the original canvas by attaching a new piece of linen to its back, a traditional way of supporting a fragile canvas painting. In 1940, however, another restorer who worked in the Philadelphia area, Hannah Mee Horner, removed Stevenson’s lining and glued the painting to a plywood backing. She performed this unusual (and often problematic) treatment on many paintings in the 1930’s and ’40’s, assuming that plywood would offer superior support. However, The Gross Clinic was too large (8 by 6 ½ feet) to be backed with a single sheet of plywood, so Horner made the backing from two pieces, nailed side-by-side to a wooden framework. The seam between the pieces ran horizontally, across the middle of the painting, right at the level of Dr. Gross’s shoulders. By 1961, Siegl observed that this unconventional backing was creating serious problems of its own. The flexing and warping of the plywood pieces along the seam was causing a deformation visible on the front of the painting, a worrying crease that was threatening to split the canvas. That was not all: the heads of many of the nails driven through the pieces of plywood to join them to the wood framework had begun to work forward, pushing against the back of the fragile canvas, threatening to puncture it, and causing rows of unsightly bumps on the painting and some small losses of paint.

The need for immediate action to keep more damage from occurring was clear. Siegl examined the painting thoroughly, developed a plan to address its problems, and submitted his findings and a treatment proposal to the then-owner of the painting, Jefferson Medical College. The project was approved right away and work began. As required by professional standards of the conservation field, this time the condition of the painting and all work carried out was carefully documented with written records and photographs, before, during, and after the treatment.

Theodor Siegl, Philadelphia Museum of Art Conservator, at work on The Gross Clinic, 1961

Over the summer of 1961 Siegl and his team, including the artist Louis B. Sloan, labored to remove the plywood from the back of the canvas without causing any further damage. The painting was secured face-down on a large table constructed for the purpose, with the paint surface protected by layers of tissue and fine cotton cloth temporarily attached to it. Then the backing had to be shaved away in stages, the first plies by controlled use of an electric planer, and the rest with scalpels and other hand tools. Finally, Horner’s thick layer of glue was removed from the canvas itself. Once that was accomplished, the painting could be lined again in a conventional fashion, attaching a strong new piece of linen to the back of the original canvas. The tissue and cloth that had protected the face of the painting throughout the processes of backing removal and lining were removed and the painting was mounted on a new stretcher (an expandable wood framework for supporting painting canvases), completing the structural-preservation phase of the treatment.

The next step was to clean the painting. Siegl was intent on carrying this out in strict accordance with the absolute standard of responsible cleaning: that the removal of non-original materials—such as restorers’ varnishes and retouching—can proceed only if it can be accomplished without the slightest harm to the original paint. The 1961 cleaning required the removal of coats of varnish that restorers had applied to the painting’s surface in attempts to freshen up its appearance, but that had since yellowed and darkened. Siegl determined the proper combination of solvents that would allow the removal of the varnish, a small area at a time, without disturbing the original paint. He also painstakingly removed the accumulation of several earlier restorers’ retouching that covered old punctures and tears. Much of this retouching, some of it very tough and resistant, was disturbingly apparent due to poor color matching, and covered more than just the damages, extending well beyond, hiding Eakins’s paint.

Louis B. Sloan, who assisted with the 1961 treatment, removing the first plies of the 1940 plywood backing.

The removal of all of the obscuring non-original materials from the surface clarified what was truly Eakins’s own paint, but it also confirmed what had already been noted in the pre-treatment examination—that earlier restorers who had lacked the knowledge and skill necessary to clean the painting safely had worn away upper layers of Eakins’s paint in some places. After the 1961 removal of the old varnishes and retouching was complete, Siegl applied a new coat of colorless varnish to saturate the colors and protect the paint surface. The new varnish was also intended to isolate the 1961 conservation team’s new retouching from Eakins’s own paint, so the restoration materials would remain physically separate and easily distinguishable from the original paint. In their retouching (often called “inpainting” because it is carefully applied only within the boundaries of loss) the 1961 team concealed what was felt at the time to be the most visually disruptive damages. The materials they used for this were chosen to allow their safe removal in the future if it should become necessary. This kind of foresight, a foundation of professional practice, acknowledges the possibilities that the inpainting could eventually shift in color and become conspicuous, the varnish could discolor or present concerns about its easy removability, or the extent of restoration might require rethinking. Now, 48 years later, The Gross Clinic, and the public for whom it is held in trust by the two museums responsible for its care, are the beneficiaries of the professional, conscientious approach taken by Theodor Siegl and his team.